CN113402769A

CN113402769A - Hydrophobic sponge material for profile control and water shutoff of oil field and preparation method thereof

Info

Publication number: CN113402769A
Application number: CN202110720091.6A
Authority: CN
Inventors: 冯玉军; 欧文; 罗新杰
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2021-06-28
Filing date: 2021-06-28
Publication date: 2021-09-17
Anticipated expiration: 2041-06-28
Also published as: CN113402769B

Abstract

The invention discloses a hydrophobic sponge material for profile control and water shutoff of an oil field and a preparation method thereof, wherein the method specifically comprises the following steps: crushing the sponge material, soaking in a metal salt solution, fully stirring at normal temperature, filtering, and drying at constant temperature to obtain the hydrophobic sponge powder material. The method has the advantages of simple production process, mild reaction conditions, low energy consumption and low preparation cost. The hydrophobic sponge material prepared by the method has high hydrophobicity and repellency to water flow, so that water generates larger resistance when passing through the sponge material, the resistance to oil phase is smaller, and selective water plugging can be realized. The material is used as a selective water shutoff and profile control substitute material, and can expand swept volume after plugging a high-permeability channel, thereby meeting the requirements of profile control and water shutoff of cracks and large channels.

Description

Hydrophobic sponge material for profile control and water shutoff of oil field and preparation method thereof

Technical Field

The invention belongs to the field of functional materials and oil and gas exploitation, and particularly relates to a hydrophobic sponge material and a preparation method thereof.

Background

Most oil fields in China are developed by water injection. When water is injected for displacement of reservoir oil, water tends to flow through high-permeability strips or cracks and bypass a compact oil-containing layer, so that an injection profile has strong heterogeneity, and an oil well generates unnecessary water production. Oil well water production and heterogeneous injection profiles can present operational and economic problems such as reducing the production life of the oil well, increasing the water content of the produced fluids, corroding equipment, scaling of the oil reservoir, increasing oil-water separation and transportation costs. Therefore, profile control and water shutoff technology is needed to adjust the flow profile of the water injection well and control the excess water output of the production well.

Early attempts to use cement, silicates, etc. as water control materials to plug high permeability thief zones, but these materials did not effectively penetrate low permeability zones and they would plug the oil and water passages non-selectively. In addition, the polymer solution and the gel solution are also used as profile control water shutoff materials, have stronger penetrating power, can enter a low-permeability layer, are adsorbed and retained in a porous medium, and can selectively block water, so that the reduction degree of the water phase permeability is greater than that of the oil phase permeability. However, the polymer has limited strength and cannot meet the requirements of profile control and water shutoff of cracks and large channels; the gel is generally prone to cracking in the wider channels and dehydration occurs in the high temperature, highly mineralized downhole environment.

Aiming at the defects of the conventional profile control and water shutoff material, a simple, convenient, economical and stable selective water shutoff and profile control alternative material is needed. In recent years, some new hydrophobic materials have been used for oil-water separation due to their specific selectivity for oil and water. Many materials, such as metal meshes, membranes, sponges, fabrics, etc., can be modified into highly hydrophobic or superhydrophobic matrix materials to separate oil and water mixtures. For example, oil-water separation is performed using a super-hydrophobic stainless steel net, and when an oil-water mixture is poured onto a mesh, an oil phase passes through and a water phase is blocked on the mesh. The super-hydrophobic melamine sponge is a common oil-water separation material. The material has an open pore structure, can be used as an oil absorption material and a filter material, and the super-hydrophobic surface of the material can prevent water from entering the material. However, the above separation processes are all carried out on the ground at room temperature and ambient pressure, and there are few profile control and water shutoff processes involving the use of hydrophobic materials in petroleum production processes.

Disclosure of Invention

The invention aims to provide a hydrophobic sponge material for profile control and water shutoff of an oil field and a preparation method thereof aiming at the defects of the prior art, so as to obtain a simple, convenient, economic and stable hydrophobic melamine sponge material, and the hydrophobic melamine sponge material is used as a selective water shutoff and profile control substitute material to meet the requirements of profile control and water shutoff of cracks and large channels.

The mechanism of the method is as follows: the chemical structure of the melamine sponge material contains a large amount of N, O atoms, so that the surface of the material has strong polarity. N, O atoms have a coordination function between lone pair electrons and metallic aluminum ions, so that the surface chemical environment is reconstructed, the polarity of the surface of the material is reduced, and the surface energy of the material is reduced, therefore, the surface of the material is changed from hydrophilic to hydrophobic. The hydrophobic material has a repulsive effect on water, and the material can selectively reduce the water phase permeability by virtue of the physical blocking effect of the material.

The invention provides a hydrophobic sponge material for profile control and water shutoff of an oil field and a preparation method thereof, wherein the preparation method comprises the following steps:

(1) crushing the modified matrix sponge material to obtain sponge powder particles with a certain particle size;

(2) mixing the sponge powder particles obtained in the step (1) with a hydrophobic modified metal salt solution, stirring at normal temperature, filtering, and drying to obtain a hydrophobic sponge powder material;

wherein the mass ratio of the sponge powder particles to the metal salt is 10 (1-20).

In the method, the sponge material is thermosetting melamine sponge, and the structural formula of the repeating unit is shown in the specification

In the method, the step (1) of crushing the sponge material comprises the steps of crushing the sponge material into small pieces, and then putting the small pieces into a crusher to be crushed for 4-8 min.

In the method, the particle size of the sponge material obtained in the step (1) is 1-100 μm.

In the method, the metal salt solution in the step (2) is AlCl₃An aqueous solution, the metal salt being aluminum chloride hexahydrate (AlCl)₃·6H₂O)。

In the method, the preparation of the hydrophobically modified metal salt solution in the step (2) is to mix the metal salt and water according to the mass ratio of 1 (40-400).

In the method, the stirring time in the step (2) is 2-5 hours, and the drying temperature is 80-100 ℃.

The invention provides the hydrophobic sponge material for profile control and water shutoff of the oil field, which is prepared by the method. The hydrophilic contact angle of the hydrophobic sponge material is above 130 degrees.

The invention also provides application of the hydrophobic sponge material prepared by the method in the field of profile control and water shutoff of oil fields.

Compared with the prior art, the invention has the following beneficial effects:

1. the selected matrix material is commercial melamine sponge, which has soft texture, low price and wide source and can be crushed into powder to enter the stratum.

2. The invention selects metal aluminum salt as the reagent for hydrophobic modification of melamine sponge, and has the advantages of wide source, low price, environmental protection and no pollution.

3. The hydrophobic sponge material is a thermosetting material, can keep stable performances such as strength and the like in a complex oil reservoir environment, and can meet the requirements of profile control and water shutoff of cracks and large channels.

4. The hydrophobic sponge material disclosed by the invention has repellency to water, can increase water phase resistance after being blocked, and can selectively reduce water phase permeability.

5. The method has the advantages of simple production process, mild reaction conditions, low energy consumption and low preparation cost, and is beneficial to industrial production and practical application.

6. The hydrophobic sponge material has a certain particle size, is injected underground and preferentially enters a high-permeability channel or a crack, and has small damage to a low-permeability layer.

Drawings

FIG. 1 is a graph showing the results of water contact angle of the hydrophobically modified samples obtained in examples 1 to 16.

FIG. 2 is an IR spectrum of a sample M50-4 obtained in example 11 together with an unmodified sample.

FIG. 3 is a XPS comparison of sample M50-4 obtained in example 11 with an unmodified sample (A is a full spectrum, B, C, D is a high resolution spectrum corresponding to Al, O and N elements, respectively)

FIG. 4 is a comparative Scanning Electron Microscope (SEM) photograph of the sample M50-4 obtained in example 11 and an unmodified sample (FIG. A, B is a sample before modification, and FIG. C, D is a sample after modification).

FIG. 5 is a graph showing the results of the oil-water filtration test on the sample M50-4 obtained in example 11.

FIG. 6 is a graph (A) showing the pressure change with the injection volume and a comparison graph (B) showing the permeability of the water phase and the oil phase before and after plugging, in the selective water plugging test using the sample M50-4 obtained in example 11.

FIG. 7 is a graph comparing the change in the split flow rate between a fractured core and a non-fractured core of a parallel profile test using sample M50-4 obtained in example 11.

Detailed Description

The hydrophobic sponge material for profile control and water shutoff of the oil field and the preparation method thereof are further explained by the specific embodiment.

In the following examples, a raw melamine sponge (density 9 kg/m)³) Purchased from Beijing Kelin Mei high New materials, Inc.; cross-linking agent aluminium chloride hexahydrate (AlCl)₃·6H₂O), (purity 98%) purchased from zheng state pani reagent factory; the deionized water for experiments is self-made by a laboratory ultrapure water machine, and the conductivity of the deionized water is 18.25 mu S-cm^-1

Example 1

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; 0.06g of AlCl is subsequently added₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 2 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M5-2.

Example 2

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.12g AlCl₃·6H₂O solid dissolved in 50mLPouring ultrapure water into a reaction beaker, stirring for 2h at normal temperature, then performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying at 85 ℃ to obtain the hydrophobic sponge powder material, which is recorded as M10-2.

Example 3

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.6g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 2 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M50-2.

Example 4

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 1.2g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 2 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M100-2.

Example 5

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; 0.06g of AlCl is subsequently added₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 3 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M5-3.

Example 6

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.12g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 3 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M10-3.

Example 7

Pulverizing melamine sponge for 4min to obtain melamine sponge particles, and weighing 0.6g melamine spongePlacing the granules into a beaker; then 0.6g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 3 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M50-3.

Example 8

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 1.2g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 3 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M100-3.

Example 9

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; 0.06g of AlCl is subsequently added₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 4 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M5-4.

Example 10

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.12g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 4 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M10-4.

Example 11

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.6g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 4 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M50-4.

Example 12

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 1.2g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 4 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M100-4.

Example 13

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; 0.06g of AlCl is subsequently added₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 5 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M5-5.

Example 14

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.12g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 5 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M10-5.

Example 15

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 0.6g AlCl₃·6H₂And dissolving the O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 5 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain the hydrophobic sponge powder material, wherein the mark is M50-5.

Example 16

Putting the melamine sponge into a grinder to be ground for 4min to obtain melamine sponge particles, weighing 0.6g of the melamine sponge particles and putting the melamine sponge particles into a beaker; then 1.2g AlCl₃·6H₂Dissolving O solid in 50mL of ultrapure water, pouring the solution into a reaction beaker, stirring the solution at normal temperature for 5 hours, performing suction filtration on the reaction mixture, putting the reaction mixture into an oven, and drying the reaction mixture at 85 ℃ to obtain a hydrophobic sponge powder material, wherein the mark is M100-5。

Example 17 Water contact Angle characterization

The modified sponge powders obtained in examples 1 to 16 were pressed into tablets and their Water Contact Angle (WCA) was measured using a Kruss DSA25 optical contact angle measuring apparatus in Germany. The measurement process is as follows: at normal temperature and pressure, 8 μ L of ultrapure water was dropped on the surface of the sample with a micro-syringe, and then an image was taken, and the contact angle was determined by Young-Laplace fitting. The error was minimized by measuring the WCA values at 4 different locations on the sample and arithmetic averaging.

The test results are shown in FIG. 1. As can be seen from the water contact angle test results, all samples had WCA values higher than 130 °, exhibiting a high degree of hydrophobicity, indicating that the melamine sponge powder has been successfully modified to a hydrophobic melamine sponge powder. The difference in contact angles for all samples was within 10 deg., indicating AlCl₃The concentration of the solution and the treatment time have less influence on the hydrophobicity of the sample.

Example 18 chemical Structure characterization

The chemical structure of the sample M50-4 obtained in example 11 was characterized by means of a Fourier transform infrared spectrometer (FTIR, Nicolet, USA) and an unmodified sample was used as a control. The specific operation is as follows: taking a small amount of dried sample, mixing with potassium bromide according to the proportion of 1:100, grinding, and tabletting; then placing the sample into an infrared spectrometer for infrared scanning, wherein the scanning wavelength range is 4000-400 cm^-1。

The IR spectrum of sample M50-4 and the original sample are shown in FIG. 2, with the two sample lines being similar, but at wavenumbers of 2944, 1476, 1331 and 1159cm^-1The vibration peaks at the points are towards 2936, 1474, 1329 and 1156cm respectively^-1The low wavenumber shift at (b) corresponds to the chemical bond C-H, C ═ N, C-O, indicating that sample N, O atoms form coordination bonds with metallic aluminum ions, thereby changing the surface wettability.

Example 19 elemental characterization

The chemical states of the elements in the sponge and the surface thereof were analyzed by x-ray photoelectron spectroscopy (XPS, Axis Ultra DLD, Kratos, UK) using the sample M50-4 obtained in example 11 as an example, and an unmodified sample was used as a control. The incident radiation was monochromatic Al K α X-rays (1486.6eV), the X-ray power for a full spectrum scan was 75W (15kV,5mA), and the X-ray power for a high resolution scan was 150W (15kV,10 mA). The binding energy for the full spectrum scan was the peak C1s at 285eV, and the binding energy for the high resolution scan was the peak C1s at 284.6 eV.

FIG. 3 shows XPS spectra of sample M50-4 and the original sample. It can be seen from the figure that the spectrogram of the sample M50-4 has more aluminum elements than the original sample, and the O1s peak and the N1s peak are shifted toward the direction of high binding energy from the spectral analysis, which further shows that the metallic aluminum ions and N, O on the sample surface undergo a coordination reaction, so that the chemical environment of the sample surface is reconstructed, the polarity of the sample surface is reduced, and the wettability of the sample surface is changed.

Example 20 surface topography Observation

Taking the sample M50-4 obtained in example 11 as an example, gold spraying treatment was performed on the surface of the sample, and the surface morphology of the sample was observed by a scanning electron microscope (SEM, JSM-5900LV, JEOL, Japan) at an acceleration voltage of 15kV, and an unmodified sample was used as a control.

SEM images of sample M50-4 and the original sample are shown in FIG. 4. By analyzing and comparing SEM images of samples before and after modification, the overall structure of the modified sponge powder particles is not obviously changed, but the surface of the modified sponge powder particles is relatively rough, which shows that the change of the surface roughness increases the hydrophobicity of the modified sample to a certain extent.

Example 21 filtration experiment

Using the sample M50-4 obtained in example 11, the modified sample was further evaluated for its different wettabilities to simulated oil (mineral oil) and water by a single-phase filtration experiment at normal temperature and pressure. First, a 2g sample of M50-4 powder was filled into a glass tube with a porous baffle, followed by a beaker to form a simple filtration unit; then 20ml of mineral oil and water were poured into the two filters respectively and the time for the liquid to completely flow into the beaker was recorded.

The experimental results are shown in fig. 5, mineral oil flows into the beaker through the filter device within 15min, and the other side water is completely blocked above the filler for at least 72h, which shows that the modified hydrophobic sponge sample has selective permeability to oil under normal temperature and pressure.

Example 22 indoor simulation of Selective Water shutoff experiments

A simulated selective water shutoff experiment was conducted using sample M50-4 obtained in example 11. Specifically, after the artificial fracture core is dried in vacuum, the size and the mass of the artificial fracture core are measured; saturating the rock core with NaCl with the mineralization degree of 15000mg/L simulated saline water under vacuum, putting the rock core into a rock core holder, adding confining pressure of 3MPa, and raising the temperature to 45 ℃; respectively injecting simulated saline and simulated oil (mineral oil) at the flow rate of 5mL/min until the pressure value is stable; the powder samples were then dispersed in a suspension (2 wt%) of silicone oil and injected into the cracks, followed by a second water and oil drive in the same manner until the pressure values stabilized. The change in pressure was recorded every minute throughout the experiment. And respectively calculating the water phase permeability and the oil phase permeability of the first water flooding and the second water flooding according to the Darcy formula.

Fig. 6 contains a graph (a) of the pressure change throughout the plugging process and a comparison graph (B) of the water phase and oil phase permeability before and after plugging. As can be seen from the figure, the pressure of water drive and oil drive is increased after plugging, but the water drive pressure is increased more than that of oil drive, the corresponding water phase permeability is reduced more than that of oil phase, and the ratio of the oil phase permeability to the water phase permeability is increased from 0.8 to 2.5 after plugging, which shows that the plugging material has certain selective plugging capability to the oil phase and the water phase.

Example 23 measurement of Water content in Sand-packed pipe model

A simulated oil displacement experiment was performed at 45 ℃ by using the sample M50-4 obtained in example 11 and a quartz sand filling pipe model of 70-120 meshes, and the change in water content within 40 minutes was measured, and the sand filling pipe model completely filled with quartz sand was used as a control group. Mineral oil was used as the simulated oil (stained with oil red O to distinguish from water) for this test, and the NaCl simulated saline salinity was 15000 mg/L. The specific experimental process is as follows: the sand-packed pipe model is saturated with brine and then saturated with mineral oil, and in the two processes, parameters such as porosity, permeability, saturated oil volume and the like of the sand-packed model are determined; and then, performing water flooding at the flow rate of 2ml/min for 40min, and measuring the volume of the collected oil and water, wherein the water content is the ratio of the volume of the water phase collected at the outlet end to the total volume of the liquid.

The parameters of the sand-filled pipe model and the final water content result are shown in table 1, and the parameters of the sand-filled pipes of the experimental group and the control group are similar except for different fillers, so that the parameters are compared. The water content result shows that the water content of the outlet of the sand-filled pipe model filled with the modified sample is reduced by about 7.4 percent compared with that of a control group, which indicates that the modified sample has certain capability of reducing the water outlet of an oil well.

TABLE 1 Sand pack pipe model parameters and Final Water content

Example 24 parallel core Profile control experiment

A parallel core profile control experiment was performed at 45 ℃ using sample M50-4 obtained in example 11. Specifically, 2g of sample M50-4 was first dispersed in 100g of silicone oil to form a suspension; after the artificial fractured core (432mD) and the non-fractured core (96mD) were vacuum-dried, the size and mass thereof were measured; saturating the rock core with NaCl with the mineralization degree of 15000mg/L simulated saline water under vacuum, putting the rock core into a rock core holder, adding confining pressure of 3MPa, and raising the temperature to 45 ℃; then, 3 stages of injection (the flow rates of the brine and the suspension are respectively 2mL/min and 0.5mL/min) are carried out according to the sequence of the first simulated brine drive, the suspension drive and the post-brine drive, the liquid production amount of each core clamp outlet is respectively recorded, and the split flow rate is calculated.

The experimental result is shown in fig. 7, when the water is driven for the first time, almost all the displacement brine flows out from the fractured core, and only a little liquid flows out from the non-fractured core outlet; after plugging is carried out, the diversion rate of the outlet of the fractured core is greatly reduced, and the diversion rate of the outlet of the non-fractured core is greatly increased. Before plugging, the permeability of the fractured core is far higher than that of a non-fractured core, liquid almost completely flows out of the fracture, and after sample suspension is injected, the fracture is plugged, the influence on the non-fractured core is small, so that the flow distribution rate of outlet ends of the two cores is changed, which shows that the sample successfully plugs the fracture, the sweep efficiency is increased, and the profile control effect is achieved.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described specific embodiments. The above-described embodiments are merely illustrative and not restrictive, and those skilled in the art can now make various changes and modifications without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. the hydrophobic sponge material for profile control and water plugging in oil field and preparation method thereof, is characterized in that, comprises the following steps:

(2) mixing the sponge powder particles obtained in step (1) with the hydrophobically modified metal salt solution, stirring at normal temperature, filtering, and drying to obtain the hydrophobic sponge powder material;

Wherein, the mass ratio of sponge powder particles to metal salt is 10:(1-20).

2. The method according to claim 1, wherein the sponge material is a thermosetting melamine sponge, and the repeating unit structural formula is

3. The method according to claim 1, characterized in that, the crushing of the sponge material in the step (1) is to first crush the sponge material into small pieces, and then put it into a pulverizer and pulverize for 4-8 minutes.

4 . The method according to claim 1 , wherein the particle size of the sponge material obtained in the step (1) is 1-100 μm. 5 .

5 . The method according to claim 1 , wherein the metal salt solution in step (2) is an AlCl ₃ aqueous solution, and the metal salt is aluminum chloride hexahydrate (AlCl ₃ ·6H ₂ O). 6 .

6 . The method according to claim 1 , wherein the preparation of the hydrophobically modified metal salt solution in step (2) is obtained by mixing the metal salt and water in a mass ratio of 1:(40-400). 7 .

7 . The method according to claim 1 , wherein, in the step (2), the stirring time is 2-5 h, and the drying temperature is 80-100° C. 8 .

8. The hydrophobic sponge material prepared by the method according to any one of claims 1 to 7 for oilfield profile control and water shutoff.

9 . The hydrophobic sponge material for profile control and water plugging in oilfields according to claim 8 , wherein the water contact angle of the hydrophobic sponge material is above 130°. 10 .

10. Application of the hydrophobic sponge material of claim 8 in the field of profile control and water shutoff in oilfields.